A camera having a flash unit fixed at a position close to the optical axis of the camera lens (as is common for compact cameras) often leads to the undesirable "red-eye" effect appearing in photographs of human subjects (as well as other mammals). In low light conditions for which a flash is used, the pupils of a human subject are dilated. Thus, when the flash emits light beams travelling close to the optical axis of the lens, the beams are reflected from the retina of the subject to produce a photograph in which the eyes appear red due to the blood vessels in the retina being visible about the dilated pupils of the subject.
Various attempts have been made in the prior art to solve the problem of red-eye. However, these devices have proven not to be completely satisfactory as they are often ineffective for many common applications or present complicated assemblies which increase the probability of failure, increase expense and lead to an increase in assembly and set-up requirements.
U.S. Pat. No. 4,078,170 illustrates a multi-component assembly for avoiding red-eye. This assembly includes a frame structure which supports a vertically directed flash and a relatively large reflective screen assembly. The invention of U.S. Pat. No. 4,078,170 would be unsuited for many typical uses (e.g., outside photographs in windy conditions) and is difficult to set-up and disassemble for compact storage. Also, the invention of U.S. Pat. No. 4,078,170 would not be practical for many of the low cost and compact cameras which represent a large share of the camera market.
U.S. Pat. No. 4,690,531 illustrates two different embodiments wherein the flash source pops out from a retracted storage position for avoiding red-eye in narrow field of view photos. The invention of U.S. Pat. No. 4,690,531, while avoiding the problem of assembly and disassembly, relies on a relatively complicated multi-component system that is prone to breakage. Also, the limited extension of the flash limits the ability of the camera to avoid red-eye in many typical use situations. In addition, the multi-component assembly of U.S. Pat. No. 4,690,531 makes it difficult to maintain manufacturing and component costs low.
U.S. Pat. No, 4,847,647 illustrates another attempt to avoid the red-eye effect. As with the aforementioned patents, the invention of U.S. Pat. No, 4,847,647 presents a multi-component structure which would suffer from drawbacks such as high cost, an increased chance of failure and limited applicability.